Automatic gate operator

ABSTRACT

A barrier movement operator is having a position sensor in a telescoping barrier control arm is described. A controller, remote from the arm, senses the barrier position to identify limits of barrier travel and to control rate of travel of the barrier between limits. The operator includes both optical and edge sensor obstruction detectors and is responsive to wireless communication for receiving user initiated command signals.

BACKGROUND

The present invention relates to automatic barrier movement operators.

Barrier movement systems are known in the art and generally comprise amotor for moving the barrier in response to a controller whichdetermines necessary actions by responding to barrier travel limits,safety apparatus and user command input signals. With such known systemsthe travel limit determining apparatus is maintained at the controllerand represents the controller's view of the barrier. Should the barrierbe disconnected from the controller and moved, the barrier position maybecome unknown leading to lack of ability to automatically control thebarrier.

Similarly, known systems may respond to a number of safety inputdevices, such as edge contact sensors or optical obstruction detectors,which is limited by the number of input ports provided for such. This isparticularly so in commercial door operators or gate operators where theeventual equipping of the system depends on an unpredictable environmentand the needs of the users and installers of such devices. Such aproblem is quite complex for gate operators where the number ofcombinations of optical detectors and edge detectors is large anddepends on factors unknown at the time the system is manufactured.

Known systems include the ability to optionally respond to wirelesscommunications. Such systems typically require separate decoders foreach wireless transmitter or type of transmitter resulting in unduecomplexity and cost. Also known systems typically start and stop barriermovement with a linear increase and decrease of power applied to adriving motor. Such systems do not pay continuing attention to barrierposition and may result in efficient barrier movement or a barrier whichmoves too slowly or even stops before a destination limit of travel.

SUMMARY

The above disadvantages are overcome in accordance with the barriermovement operator described and claimed herein.

In accordance with one embodiment apparatus for generating positionsignals is disposed remotely from a controller of the apparatus andperiodically reports position signals to the controller. Advantageously,the position sensor may comprise circuitry for producing an analogrepresentation of position and an analog to digital convertor forperiodically reporting digital position signals to the controller.

An embodiment also includes the ability to operate with an expandednumber of safety devices such as edge contact detectors and opticalobstruction detectors. Advantageously, the two types of safety devicesproduce non-interfering normal and safety signals so that differenttypes of safety devices can be connected to the same input terminal.Upon receipt of a safety alerting signal the controller determines whichtype of device generated the signal and then performs a safety actionassociated with the signaling type of device.

The described and claimed barrier movement system also may respond towireless user commands. Advantageously, the controller includes a singledecoder which learns wireless input commands directed toward differentoperator functions such as movement of one barrier, movement of anotherbarrier and movement of both barriers. The wireless commands are learnedin a manner which can be used to duplicate the appropriate action whensubsequent receptions of the same wireless command occur during anoperate mode of the device. The fact that a received wireless commandmatches a previously learned command is reported to the controller on aseparate communication path associated with the functions to beperformed.

An improved method of setting limits of barrier travel is also describedand claimed herein. Upon initiation of a limit learn function a barrieris moved to an end limit and a command signal is sent to the controllerwhich responds by storing the end limit. The barrier is then moved tothe other end limit, the position of which is stored by the controllerin response to another command signal. The command signals may beproduced by user inter action with a command button of the controller orby wireless transmissions.

Power is reduced to the barrier moving motor when a predeterminedposition of travel is reached with regard to an end limit. Suchreduction of power is achieved by reducing the applied power in anon-linear function based on the actual position of the barrier as itslows. The non-linear reduction of power may be achieved, for example,by reducing power by a predetermined amount identified by barrierposition. Non-Linear reduction may also be achieved by calculating theamount of power needed to reduce applied power to a predeterminedminimum power. When power is being reduced it is possible that thebarrier will move too slowly or stop altogether. Advantageously, thespeed of barrier movement can be determined from recent position signalsand, when too slow, power can be increased to provide a minimum rate ofbarrier travel.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a combined schematic of an automatic gate operator;

FIG. 2 is a cross-sectional view of a telescoping used to move the gatesof FIG. 1;

FIGS. 3 and 4 show portions of the telescoping arm in retracted positionand extended position respectively;

FIG. 5 is a schematic diagram of a position sensor signal generator;

FIG. 6 is a combined block diagram and structural diagram of the safetyequipment used in a gate operator;

FIG. 7 is a block diagram of a controller for the gate operator;

FIG. 8 is a schematic diagram of electrical connections to a set ofinput terminals; and

FIGS. 9 and 10 are representations of power applied to a motor to movethe gate of the gate operator system.

DESCRIPTION

FIG. 1 represents a barrier movement operator embodied as a gate openingand closing system. Although the embodiments and examples are written interms of an automatic gate operator, it is to be understood that theprinciples discussed herein are equally applicable to other barrieroperators such as garage door operators, solid door movers and window orshutter controllers. The gate operator system includes a pair of gates11 and 13 each of which is mounted to swing from a respective post 10mounted on either side of a passageway 51 (FIG. 6). A telescoping armassembly 150 is connected between a post 10 and gate 11 and anothertelescoping arm assembly 150 is connected between the other post 10 andgate 13. The gates are individually moved by extending and retracting aportion 20 of the arm 150. The extension and retraction are controlledby signals from a control unit 15 which is in overall control of thebarrier movement system. Control unit 15 responds to user commands toopen and close the gates and also responds to feedback information fromthe telescoping arms 150 and information from photo eyes 17 and 18 andedge contact sensors 24 and 25.

A more detailed representation of a telescoping arm is presented in FIG.2. Telescoping arm 150 includes an electric motor 27 which rotates inresponse to electrical power provided from controller 15 via conductionpath 29. In the disclosed embodiment motor 27 is a DC motor respondingto pulse width modulated power however, it is to be understood thatother types of electrical motors may be used when their rotation speedand/or output power can be controlled. The power output of motor 27 isconnected by a rotation coupling 36 to a drive end 32 of a screw shaftextension. Coupling 36 provides gear reduction from motor 27 and permitsa user to decouple the motor from drive 32. The make-up of coupling 36is not described in detail herein. Drive end 32 is coupled by anextension 121 to rotate an elongated screw shaft 34.

Telescoping arm 150 comprises an outer tube 40 having therein an innerextension tube 20. A nut 102 having threads to mate with the threads ofscrew shaft 34 is disposed at an inner end of inner tube 20.Accordingly, when drive 32 is rotated, screw shaft 34 rotates and innertube 20 is extended or retracted from and into outer tube 40 dependingon the direction of rotation. The pitch of screw threads on shaft 34 issuch that on the order of 8 or 9 revolutions of shaft 34 will fullyextend or fully retract the inner tube 20. It should also be mentionedthat when the motor 27 is decoupled from drive end 32, the inner tube 20can be extended and retracted by pulling and pushing thereon. Suchmanual extension and retraction causes a rotation of screw shaft 34 inthe same amount as occurs from motor 27, when coupled.

Extension shaft 121 is coupled by means of a driving belt 120 to a 10turn potentiometer 38. The relative diameters of shaft 121 and thecontrol shaft of potentiometer 38 are such that a complete extension ofinner tube 20 results in less than 10 rotations of the potentiometershaft. Thus, the range of potentiometer is not exceeded during a fullextension or retraction of the inner tube 20. The wiper 42 ofpotentiometer is connected as an input to an analog to digital converter44 which is disposed within telescoping arm 150 along with thepotentiometer 38. As shown in FIG. 5 the fixed ends of the potentiometerresistance are respectively connected to a reference voltage and toground so that as the shaft 34 rotates, either by the action of motor 27or manual action, a variable voltage is applied to the analog to digitalconvertor 44. In FIG. 5 analog to digital converter is represented as amicroprocessor 44 which both produces digital representations of theanalog position voltage and serially transmits those digitalrepresentations from the telescoping arm 150 to the controller 15.Microprocessor 44 is programmed to periodically transmit the digitalposition representing signals approximately every 50 m sec althoughother periods of transmission could be used.

FIG. 6 is a plan view of the barrier movement apparatus showingparticularly the safety apparatus which may be associated with the gate.Posts 10 are disposed at either side of passageway 51. The gates 11 and13 are attached to posts 10 to swing in an orientation which opens andcloses access along the passageway. A plurality of photo eye pairs aredisposed to form a frame around the area over which the gates swing. Thepair of photo eyes 17-18 surveys a line across the passageway next toposts 10 while a pair of photo eyes 47-48 surveys the passageway justbeyond the ends of the open gates. Each side of the passageway may alsobe protected by a pair of photo eyes. Photo eyes 53-54 survey one sideof the passageway just outside the travel of gate 11 and photo eyes56-57 survey a similar site on the gate 13 side. The photo eyes areelectrically connected in pairs for communications with controller 15.An optical beam is normally transmitted from one photo eye e.g., 47 toanother of the pair e.g., 48. When the optical beam is properly receivedthe photo eye pair returns a predetermined voltage with periodic dropsto zero volts to the controller 15. In an embodiment the drops to zerovolts occur approximately every 7 m sec. When an obstruction breaks theoptical beam the voltage remains at the predetermined voltage levelwithout drops to zero volts and remains so until the obstruction isremoved. Controller 15 is programmed to respond to a signal identifyingan optically detected obstruction by stopping all movement of the gatesuntil the obstruction is removed and proper signals are again received.

The edge contact obstruction sensors e.g., 24 and 25 are also connectedto provide safety signals to controller 15. Edge sensors 24 and 25 arenormally open contact switches the contacts of which have apredetermined edge sensor voltage applied between them. Normally theedge sensor voltage is detected by controller 15 indicating that noobstruction has been touched. Alternatively, when an obstruction istouched the normally open contacts are shorted and the voltage detectedby the controller 15 drops to substantially zero and remains there untilthe edge sensor e.g., 24 is no longer touching an obstruction. Some edgesensors also include a known resistance connected between the sensorcontacts at one end of the edge sensor. This permits the controller 15to check for a constant current for assurances of a working sensor, buta signal of zero volts is still the safety signal. Thus, an edge safetysignal comprises a drop of voltage sensed by controller 15 tosubstantially zero volts. Controller 15 is programmed to respond to anedge sensor safety signal by reversing the travel of all moving gatesfor a fixed distance.

The safety signals from edge sensors e.g., 24 and from photo eye pairse.g., 47-48 are all applied to a set of input terminals 59 which areshown in greater detail in FIG. 8. Each input terminal 61-64 can beconnected to one or more safety devices of either optical (photo eye) oredge contact type. When both optical and contact type sensors areconnected to a terminal, that terminal will exhibit a predeterminedvoltage with near zero drops at an approximately a 7 m sec period whenneither device has an obstruction. That is, the near zero drops by theoptical sensor will pull the contact sensor voltage to zero for the timeof the drops. Should the contact sensor strike an obstruction thevoltage on the line will be pulled to a constant near zero. If insteadthe optical sensor is blocked by an obstruction the terminal will remainhigh which will be detected because the near zero drops on the inputwere present, but have gone away. Controller 15 periodically scans theinput terminals 61-64 to determine that no safety signals are present.When a safety signal is detected, controller 15 identifies whether it isan optical safety device or a contact safety device which is creatingthe signal and takes appropriate action. That is, when the detectedsafety signal is from an edge contact sensor the direction of movementis reversed and when an optical safety signal is detected, gate movementis not started or stopped if motion is occurring. The input terminals61-64 can be shared because the optical safety signal is a constantpredetermined voltage while the edge contact safety signal is a constantnear zero volt signal.

During the set up of the gate operator the controller 15 is taught theend limits of travel of the gates. First, the user presses a limit learnbutton 66 (FIG. 7) to which processor 68 of controller 15 responds byentering the limit learn mode. The user then uncouples the motor 27 fromthe extension screw 34, if not already done, and manually moves a firstgate to either the open or the closed position and signals such bypressing manual gate operator control button 70. Then the user manuallymoves the gate to the other limit position and again presses the controlbutton 70. When, as shown in FIGS. 1 and 6, two gates are present theuser repeats the process with the second gate. The controller 15 recordsin memory the digital representation of position from analog to digitalcontrollers 44 at each open and closed limit for each gate. The gate canbe controlled to move between the stored position limit values. It maybe desirable for the controller to know which stored position limitcorresponds to an open gate and a closed gate. In embodiments where suchis desired the controller is programmed to expect the position limitsfor a predetermined state such as closed first. On the preceding limitsetting process, limits were identified when a user pressed a controlbutton 70. When the barrier movement system is equipped with wirelesscommand capability (discussed below), wireless commands can also be usedto identify limits in the same manner as button 70.

The barrier movement system of the present description may also includea wireless security code transmitter 72 which can wirelessly initiatemovement of one or more of gates 11 and 13. Transmitter 72 transmitsgate commands by RF signals, however, other types of wireless signalingsuch as optical or acoustic could be used. Controller 15 includes an RFreceiver 74 which receives transmission from transmitter 72 via anantenna 76. Representations of received signals are sent to a decoder 78which validates selected received signals and notifies processor 68 viaone of a plurality of conductors of which conductor 81, 82 and 83.Validation of a received RF transmission is done on the basis oftransmitted security codes and before validation can occur, the decoder78 is taught values which are later compared to received security codesto complete validation or not.

Decoder 78 includes a microprocessor and memory which are programmed tooperate in a learn mode and in an operate mode. Although differentnumbers of such buttons could be provided, decoder 78 is connected tothree learn buttons 85, 86 and 87. In the present embodiment button 85represents a learn mode for movement of gate 13, button 86 represents alearn mode for gate 11 and button 87 represents a learn mode for bothgates.

Transmitter 72 includes three transmit buttons 90, 91 and 92, each ofwhich is associated by transmitter 74 with a unique security code. Whena transmit button e.g., 90 is pressed an RF transmission is sent whichincludes the security code unique to the pressed button. When a userwants to train the controller 15 to validate and respond to a wirelesssecurity code, such a security code must be stored by the decoder 78.When the user wants the security code to control gate 13, 11, or both, abutton 85, 86 or 87 respectively is pressed to enter the learn mode forthe correct gate or combination. The user then presses the button ontransmitter 72 which is to perform the desired control. Upon pressingthe appropriate transmitter button e.g., 90 the decoder 78, via receiver74, receives a representation of the unique code associated with button90 and stores it in a manner which identifies the gate or gates whichare to respond to the newly stored code. After the received securitycode is stored in decoder 78, the decoder switches from the learn modeto the operate mode. Subsequent receipts of the code from transmitter 72button 90 will cause decoder to send a command to processor 68 via aselected one of conductors 81, 82 or 83. The particular conductor 81, 82or 83 selected, defines whether gate 11, 13 or both are to operate.Finally, when processor 68 receives a command on one of conductors 81,82 or 83 the gate or gates associated with that conductor arecontrolled.

Processor 68 of controller 15 responds to input signals from decoder 78,command button 70 and the safety input by starting, moving and stoppingone or both gates. Such control is exercised by sending pulse widthmodulated DC to one or both of the motors 27 of telescoping arms 150. Agate is started from a first limit (limit1, FIG. 9) by applyingapproximately 25% of full power which is ramped upward to achieve 100%power at a predetermined point of gate travel X₁. The power levelremains 100% until the gate achieves a second point X₂ at which thepower is diminished until the 25% level is achieved at the destinationend point. In the embodiment represented by FIG. 9 the power is notlinearly ramped down in the reverse of the up ramp of start up power.Instead the power is non-linearly reduced to achieve a safe andefficient slowing and stopping the gate. Such non-linearly powerreduction is achieved by reducing the power based on gate position asreported by the position sensing potentiometer 38 and analog to digitalconverter 44.

In a first embodiment after gate position X₂ is achieved the power maybe reduced by a predetermined amount for each gate position reportedfrom the telescoping arm 150. Such reductions are pre-established toachieve the non-linear reduction in power represented in FIG. 9.Alternatively, power may be reduced by calculating, for each reportedgate position, the amount of power estimated to achieve 25% by thedestination limit2. In either case, the non-linear reduction is achievedby reducing power based on door position.

For reasons such as wear and tear on the gates as they age it ispossible that the forces required to move the gate may be unpredictable.When the gate is speeding up or traveling at full power such requiredforce will be overcome by the relatively high power levels. When poweris being reduced it is possible that the unpredictable forces will causethe gate to move more slowly than desired or even stop. FIG. 10represents an embodiment employed to overcome the slow or stopped gatesituation. As before the non-linear power reduction begins when aposition X₂ is indicated for the gate. As in FIG. 9 the power reductionis reduced based on gate position, however, the times and gate positionsof recent reportings are also considered to estimate the speed at whichthe gate is moving. Such speed maybe, for example, determined from thelast 5 position reports. When the speed falls below a predeterminedamount given the current gate position, the power level is increased toachieve at least a predetermined rate. In one specific embodiment if thegate position is reported as the same (no movement) for thepredetermined number of reports e.g., 5, the power is increasedbeginning at point 98 where no movement was detected. Such increasecontinues until the speed calculation indicates an adequate speed forsafety and efficiency.

1. A method of controlling a barrier moved by an electric motor towardan end limit comprising: applying a first predetermined power to themotor to move the barrier; periodically determining the position of thebarrier; reducing the power applied to the motor when the barrier is ina first predetermined position with respect to the end limit; andcontinuing to reduce the power applied to the motor while the barrier isbetween the predetermined position and the end limit by an amountdetermined by the position of the barrier and the end limit.
 2. Themethod of claim 1 wherein the step of continuing to reduce power appliedto the barrier reduces the power applied to the motor by a predeterminedamount for each period of the position determining step.
 3. The methodof claim 1 wherein the step of continuing to reduce power applied to thebarrier reduces the power applied to the motor by an amount computedfrom the difference between a determined position of the barrier and theend limit.
 4. The method of claim 3 wherein the amounts of powerreduction are computed to result in a second predetermined power beingapplied to the motor when the determined position is substantially equalto the end limit.
 5. A method of claim 4 wherein the secondpredetermined power is less than 50% of the first power.
 6. A method ofclaim 4 wherein the second predetermined power is 25% of the firstpredetermined power.
 7. A method of claim 1 wherein the step ofcontinuing to reduce the power applied to the motor reduces the power inaccordance with a non-linear function.
 8. A method of controlling themovement of a barrier moved by an electric motor toward an end limit,comprising: applying a first predetermined power to the motor to movethe barrier; periodically determining the position of the barrier;reducing the amount of power applied to the motor when the differencebetween the determined barrier position and the end limit is less than afirst predetermined amount; and after power reduction begins, increasingthe amount of power applied to the motor when successive periodicdeterminations of position indicate that the barrier is moving at a rateless than a predetermined rate.
 9. A method according to claim 8comprising continuing to reduce the power applied to the motor while thebarrier is between the predetermined position and the end limit byamounts determined by the position of the barrier with respect to theend limit.
 10. A method of claim 9 wherein the step of continuing toreduce is inhibited after the performance of the step of increasing theamount of power applied to the motor is performed
 11. A method of claim8 wherein the reducing step reduces the power applied to the motornon-linearly with regard to a determined distance between the barrierand the end position.
 12. A method of controlling the movement of abarrier moved by an electric motor toward an end limit, comprising:applying a first predetermined power to the motor to move the barrier;periodically determining the position of the barrier; reducing theamount of power applied to the motor when the difference between thedetermined barrier position and the end limit is less than a firstpredetermined amount; and after power reduction begins, increasing theamount of power applied to the motor when successive periodicdeterminations of position indicate that the barrier is moving at a rateless than a calculated rate.
 13. A method according to claim 12comprising continuing to reduce the power applied to the motor while thebarrier is between the predetermined position and the end limit byamounts determined by the position of the barrier with respect to theend limit.
 14. A method of claim 13 wherein the step of continuing toreduce is inhibited after the performance of the step of increasing theamount of power applied to the motor is performed.
 15. A method of claim12 wherein the reducing step reduces the power applied to the motornon-linearly with regard to a determined distance between the barrierand the end position.
 16. A method of controlling the movement of abarrier moved by an electric motor toward an end limit, comprising:applying a first predetermined power to the motor to move the barrier;periodically determining the position of the barrier; reducing theamount of power applied to the motor when the difference between thedetermined barrier position and the end limit is less than a firstpredetermined amount; and after power reduction begins, increasing theamount of power applied to the motor when successive determinations ofposition indicate that the barrier is not moving.
 17. A method accordingto claim 16 comprising continuing to reduce the power applied to themotor while the barrier is between the predetermined position and theend limit by amounts determined by the position of the barrier withrespect to the end limit.
 18. A method of claim 17 wherein the step ofcontinuing to reduce is inhibited after the performance of the step ofincreasing the amount of power applied to the motor is performed.
 19. Amethod of claim 16 wherein the reducing step reduces the power appliedto the motor non-linearly with regard to a determined distance betweenthe barrier and the end position.